I don't know about this x400 stuff, sounds like someone's custom number to me. But a Neutral Density filter, of between 4 and 6x will do the job. You need to choose the lowest ISO setting, small F stop, 11 or so and a slow shutter speed of 1/15th of a second at least, preferably around a second. But the 1000 does not appear to have any threading, or other provision for filters. In that case you must hold it if front of the lens.

Other than that, wait for later in the day around dusk. Use Aperture Preferred, F-11, the camera will choose a slow shutter speed hopefully without a filter, oh yes ISO 100. But no one has told you yet!, you will need a tripod.